1. Field of the Invention
The invention relates to a heat exchanger, such as an evaporator, a condenser, or the like, for a refrigerator, such as a chill cabinet, a freezer cabinet, or the like, with at least one surface provided on the heat exchanger and with which a thermal energy storage medium is in at least as far as possible heat-conducting contact.
European Patent Application 0 843 138 A1 and European Patent Application 0 714 396 A1, corresponding to U.S. Pat. No. 6,100,268 to Van Lommen et al. and to U.S. Pat. No. 5,824,682 to Van Lommen et al., each disclose a plate-like heat exchanger that in each case has a reception space for receiving a thermal energy storage medium or what is referred to as a eutectic. The reception space is, in both instances, formed by a trough-like plate wall that is secured to the plate-like heat exchanger and the free edges of which are secured to the heat exchanger in a liquid-tight manner and by the trough curvature of which the reception space for the thermal energy storage medium is formed. Although such heat exchangers bring about an improvement in the energy consumption values in refrigerators, such as, for example, chill cabinets, the construction of the heat exchanger, with its reception space for the eutectic, is, nevertheless, extremely inflexible because, if it is necessary, as required, to change the receiving capacity of the reception container and, consequently, the filling mass of the thermal energy storage medium, such a configuration necessarily requires, for the heat exchangers configured differently according to demand, a corresponding multiplicity of plate walls having differently curved shapes and influencing the receiving volume. Such a requirement contributes to the considerable increase in cost of the heat exchangers not only on account of the markedly higher logistics requirements, but also because of the different tools necessary due to the different configuration of the curved wall plates. Moreover, the configuration, existing in the prior art, of the reception space for the eutectic entails the risk of potential leakages due to the relatively complex construction of the heat exchanger plates. Furthermore, the principle, existing in the prior art, for providing a reception space for a thermal energy storage medium means a complete departure from conventional heat exchanger plates, in particular, evaporator plates, when the aim is to improve the energy efficiency of refrigerators.
It is accordingly an object of the invention to provide a heat exchanger, such as evaporator, condenser, or the like that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that, by simple structure measures, avoids the disadvantages occurring in the prior art.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a heat exchanger for a refrigerator including at least one separate reception container receiving a thermal energy storage medium and having at least one flexurally slack container wall bearing at least approximately in heat-conducting contact against the thermal energy storage medium dependent upon the flexurally slack properties of the container wall. The heat exchanger can be an evaporator or a condenser, and the refrigerator can be a chill cabinet or a freezer cabinet.
In accordance with another feature of the invention, there is provided a separate reception container that serves for receiving the thermal energy storage medium and that has at least one approximately flexurally slack container wall that, by virtue of its flexurally slack properties, can come to bear at least approximately in heat-conducting contact against the heat exchanger.
By providing at least one separate container uncouplable from the heat exchanger for receiving the thermal energy storage medium, conventional heat exchanger configurations can be combined with the reception container and, therefore, with the thermal energy storage medium to give a marked refrigerator energy saving that may be, for example, in the range of between 5 and 15%. Due to the combination possibility and to the use of conventional heat exchangers that is afforded thereby, there is no need, with a view to the use of thermal energy storage media, to have a new heat exchanger configuration, as a result of which not only is cost-intensive development and construction work avoided, but at the same time the costs incurred in producing the new heat exchanger configurations no longer arise. By providing a separate reception container, the container can be adapted particularly specifically and, therefore, with high efficiency in terms of its size, its filling with a thermal energy storage medium and its degree of filling to a predetermined application, for example, for an evaporator of a chill cabinet or an evaporator of a freezer cabinet. Furthermore, the separate reception container makes it possible to have a manufacturing sequence that is entirely independent of the heat exchanger manufacture and is, therefore, extremely flexible, such as, for example, in terms of the material used for producing it, its size and geometry and also its filling with the thermal energy storage medium.
In accordance with a further feature of the invention, the reception container is formed at least as far as possible from flexurally slack material.
What is to be meant in this connection by flexurally slack material is a material that is resilient and can be adapted at least as far as possible to differently configured surface contours. Adaptation is, at the same time, to be capable of taking place with relatively little effort. For example, film-like thin-walled materials are to be included here.
By the provision of the reception container being of material that is flexurally slack on all sides, in series manufacture it can be brought, barrier-free and, therefore, in a particularly simple way, especially efficiently into heat-conducting contact with the heat exchanger, for example, in the form of an evaporator plate or of a wire-tube evaporator. Moreover, reception containers formed from flexurally slack material can be inserted quickly and without much force into the interspace produced by the wire bars in wire-tube evaporators.
In accordance with an added feature of the invention, there is provided an evaporator plate having heat exchange surfaces, one of the heat exchange surfaces being substantially disposed in heat-conducting contact with the flexurally slack container wall of the reception container and being approximately liquid-tightly coupled to the one heat exchange surface.
In accordance with an additional feature of the invention, the reception container has a size adapted substantially to dimensions of the evaporator plate at least on the flexurally slack container wall in heat-conducting contact with the evaporator plate.
A plate-like evaporator, such as, for example, what is referred to as a coldwall evaporator produced by the roll-bonding method, can be produced particularly simply when, in accordance with yet another feature of the invention, there is provided a, the heat exchanger is configured as an evaporator plate and is connected on one of its heat exchange surfaces to the flexurally slack wall of the reception container at least as far as possible heat-conductively and at least approximately in a liquid-tight manner.
In a heat exchanger configured as a coldwall evaporator, the reception container is manufactured from a material resistant and diffusion-tight to the thermal energy storage medium and having a temperature resistance of at least 170xc2x0 Celsius. By virtue of the configuration of the flexurally slack wall in relation to the evaporator plate, particularly intensive heat-conducting contact between the reception container and the evaporator plate is produced because the flexurally slack wall fits snugly against different contours of the evaporator plate, such as, for example, the duct pattern of the latter. The possibility of the separate manufacture of the reception container, on one hand, and of the evaporator plate, on the other hand, makes it feasible to employ the conventional successfully proved manufacturing process for the latter.
The reception container, which is in heat-conducting contact with the evaporator plate, has a particularly beneficial effect on energy saving in refrigerators when, in accordance with yet an added feature of the invention, the reception container is adapted, at least on its flexurally slack wall that is in heat-conducting contact with the evaporator plate, at least as far as possible to the dimensions of the evaporator plate.
In accordance with yet a further feature of the invention, there is provided a wire-tube evaporator system having a meandering refrigerant line and wire-bar planes spanning the refrigerant line, the evaporator system including the reception container disposed between the wire-bar planes.
In accordance with yet an additional feature of the invention, there is provided a substantially pierce-resistant protective casing, the reception container being disposed between the wire-bar planes and being surrounded by the casing.
The reception container filled with the thermal energy storage medium can be brought into heat-conducting contact in a particularly simple and extremely efficient way with a heat exchanger configured as a wire-tube evaporator when, according to an alternative embodiment of the subject of the invention, the heat exchanger is configured as a wire-tube evaporator and, between its wire-bar planes spanning a meander-like refrigerant line, is equipped with at least one reception container.
By the reception container being produced from material that is flexurally slack on all sides, the reception container can be inserted quickly and easily between the wire-bar planes even when it is in the state filled with eutectic solution, particularly intensive heat-conducting contact both with the wire-bar planes and with the meander-like refrigerant line being achieved by the flexurally slack walls of the reception container.
In accordance with again another feature of the invention, the reception container disposed, in the case of a wire-tube evaporator, between the wire-bar planes of the latter is surrounded by an at least pierce-resistant protective casing. The configuration ensures, in a simple way, that the reception container formed from flexurally slack material is not inadvertently damaged.
The reception container can be produced from flexurally slack material particularly simply and cost-effectively when, in accordance with again a further feature of the invention, the reception container is configured at least approximately in the manner of a bag. By virtue of such a configuration, the reception container, after being filled with a thermal energy storage medium, can be closed in a liquid-tight manner cost-effectively by conventional closing techniques, such as, for example, welding or the like.
In accordance with again an added feature of the invention, the bag is subdivided in terms of its reception space into at least two partial volumes subdividing its receiving volume and independent of one another.
By the receiving volume of the baglike reception container being subdivided into, for example, a plurality of partial volumes completely separate from one another, it becomes markedly easier to handle the reception container in the manufacturing sequence of the heat exchangers and of the refrigerators equipped with them because of the relatively small quantity of thermal energy storage medium associated with a partial volume. Should the baglike reception container having a plurality of partial volumes subdividing its receiving volume be used in a vertically disposed refrigerator evaporator plate, the partial volumes ensure that, despite the reception container being disposed vertically, the thermal energy storage medium is distributed substantially uniformly over the evaporator surface that is in heat-conducting contact with the reception container. In addition, the division of the receiving volume of the reception container into a plurality of partial reception spaces in the case of what are referred to as coldwall evaporators prevents the foaming heat insulation material from forcing together the liquid thermal energy storage medium in a direction predetermined by the foam filling of the heat-insulating housing of a refrigerator and, consequently, the large-area contact of the thermal energy storage medium with the evaporator plate from being canceled.
In accordance with again an additional feature of the invention, the reception container is formed from a metallic material with a film-like material zone. By the reception container being produced from film-like metals, such as, for example, aluminum, high-grade steel, or the like, a relatively pierce-resistant reception container for the liquid eutectic is provided, without an additional protective casing. When an aluminum film is used, not only is a particularly beneficial transmission of heat to the heat exchanger achieved, but, in the case of plastic coating, by which the film side surrounding the receiving volume of the reception spaces is given a plastic layer, the reception container formed from an aluminum film can be cost-effectively closed in a liquid-tight manner, for example by welding.
A liquid-tight reception container with partial reception spaces subdividing its receiving volume can be produced particularly cost-effectively when, n accordance with still a further feature of the invention, there is provision for the reception container to be formed from a plastic film.
A reception container is configured particularly advantageously with regard to heat transmission, on one hand, and to a liquid-tight closure of the partial reception spaces receiving the partial volumes, on the other hand, when, in accordance with still an added feature of the invention, the reception container is formed from a plastic-coated aluminum film.
In accordance with a concomitant feature of the invention, the reception container, in terms of its receiving volume formed by the reception space or in terms of each partial receiving volume of a reception space, corresponds at least to the volume of the thermal energy storage medium in the solid state of aggregation. Such a configuration ensures that the increase in volume of the thermal energy storage medium changing from the liquid to the solid state of aggregation does not lead to the reception container being destroyed.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a heat exchanger, such as evaporator, condenser, or the like, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.